The present invention relates to a communication terminal apparatus and a method to form a group consisting of a plurality of terminals and to mutually communicate information in the group.
Recently, as a data communication interface in a personal computer or an information portable terminal, an optical communication of an infrared ray is used. As a standard protocol for this optical communication, IrDA (Infrared Data Association) is used.
In recent information portable terminals, the infrared ray communication function of the standard protocol xe2x80x9cIrDAxe2x80x9d is loaded. However, the infrared ray communication function supports a communication function of one-to-one type only. Accordingly, use the infrared ray communication function of the standard protocol xe2x80x9cIrDAxe2x80x9d, communication among a plurality of the terminals is impossible.
In this place, assume that a relay communication between IrDA terminal and LAN (Local Area Network) terminal is executed through a relay terminal. FIG. 1 shows communication between IrDA terminal Cc and LAN terminal C1 executed through relay terminal Cs. In this case, a communication speed of IrDA is low in comparison with LAN. Therefore, if the relay terminal Cs simply transmits information from LAN to IrDA, traffic on IrDA greatly increases. As a result, packet-abolishment occurs in the IrDA terminal and transmission efficiency decreases.
Furthermore, in the prior art, the relay terminal does not multicast among a plurality of terminals including the IrDA terminal and the LAN terminal. Therefore, each terminal often receives unnecessary information. For example, in FIG. 1, the LAN terminal receives information used for the IrDA terminal only and the IrDA terminal receives information used for the LAN terminal only. In this case, the quality of each terminal goes bad.
However, the IrDA terminal is small, portable, and will be more widely used as a personal handy terminal in near future. On the other hand, in an office environment, the LAN terminal is normally used by many businessmen. Therefore, the IrDA terminal must be connected to a LAN if necessary and a transmission of information must be smoothly executed between the IrDA terminal and the LAN terminal.
As mentioned-above, even if the IrDA terminal prepares one-to-one communication function, it is necessary that the IrDA terminal is connected to the LAN network and information is smoothly communicated between the IrDA terminal and the LAN terminal. Furthermore, it is necessary that the traffic on IrDA as communication means of low transmission speed goes down and the load of operation on this network system is canceled.
It is an object of the present invention to provide a communication terminal apparatus to smoothly connect the IrDA terminal as one-to-one communication function to the LAN network system including the LAN terminals.
It is another object of the present invention to provide a communication terminal apparatus to reduce the traffic on the IrDA as communication means of low transmission speed in order to cancel the load of operation on the network system.
According to the present invention, there is provided a communication terminal apparatus used in a communication system including at least one first terminal having an optical communication means for optically communicating with one other first terminal and for sending an identifier to discriminate the at least one first terminal, and at least one second terminal having a network communication means for communicating with a plurality of other second terminals by a network and for sending an identifier to discriminate the at least one second terminal, said communication terminal apparatus being a relay terminal to communicate between the first terminal and the second terminal, comprising: an optical communication means for optically sending and receiving information with respect to the at least one first terminal; a network communication means for sending and receiving information with respect to the at least one second terminal by the network; an identifier sending means for sending an identifier to discriminate the relay terminal through said optical communication means and said network communication means; a communicatable terminal discrimination means for discriminating the terminal communicatable with the relay terminal according to identifiers received from said optical communication means and said network communication means; a communicatable terminal memory means for storing the identifiers of the communicatable terminals and an attribute representing the kind of said communication means from which each identifier is received; and a received information sending means for comparing a destination identifier of received information with the identifiers stored in said communicatable terminal memory means, and for supplying the received information to said optical communication means or said network communication means according to the attribute of the identifier matched with the destination identifier.
Further in accordance with the present invention, there is also provided a method for controlling a relay terminal used in a communication system including at least one first terminal having an optical communication means for optically communicating with one other first terminal and at least one second terminal having a network communication means for communicating with a plurality of other second terminals by a network, each terminal sends an identifier to discriminate its own terminal, comprising the steps of: optically communicating with the at least one first terminal; communicating with at least one second terminal by the network; discriminating the terminal communicatable with the relay terminal according to identifiers received from the first terminal and the second terminal; storing the identifiers of the communicatable terminals and an attribute representing the kind of communication from which each identifier is received; comparing a destination identifier of information received from the first terminal or the second terminal with the stored identifiers; and supplying the received information to the first terminal or the second terminal according to the attribute of the stored identifier matched with the destination identifier.
Further in accordance with the present invention, there is also provided a computer readable memory containing computer readable instructions to control a relay terminal used in a communication system including at least one first terminal having an optical communication means for optically communicating with one other first terminal and at least one second terminal having a network communication means for communicating with a plurality of other second terminals by a network, each terminal sends an identifier to discriminate its own terminal, comprising: instruction means for causing a computer to optically communicate with the at least one first terminal; an instruction means for causing a computer to communicate with the at least one second terminal by the network; an instruction means for causing a computer to discriminate the terminal communicatable with the relay terminal according to identifiers received from the first terminal and the second terminal; instruction means for causing a computer to store the identifiers of the communicatable terminals and an attribute representing the kind of communication from which each identifier is received; an instruction means for causing a computer to compare a destination identifier of information received from the first terminal or the second terminal with the stored identifiers; and an instruction means for causing a computer to supply the received information to the first terminal or the second terminal according to the attribute of the stored identifier matched with the destination identifier.